I empathise with the OP's frustration, but the ladies and Cable have summed it up very well.
Escorts unfortunately, put up with far more time wasters than punters do.
It is incredibly frustrating to be stood up, but as a client, you can choose to see another escort and not go back to the one who stood you up. However, I would like to comment on the frequency the OP called the said lady. If she doesn't answer I'd give it about 15 minutes before trying again. She might be in the shower as one of the ladies commented. Calling repeatedly doesn't serve any purpose and will likely get the lady very suspicious.
I pretty much just revisit ladies I already know these days. And have never been stood up since!!!
"Don't be reckless with other people’s hearts. Don't put up with people who are reckless with yours"